Data centers have a specific set of issues that they must face in relation to power supply and management. Traditional techniques in this area were developed from prior industrial electrical practice in a time when a typical data center held very small numbers of mainframe computers and the change rate was low. Now, data centers often contain tens of thousands of electronic data processing (EDP) devices with high rates of change and growth. Data centers are also experiencing rapidly growing power capacity demands driven, for example, by central processing unit (CPU) power consumption that is currently increasing at a rate of approximately 1.2 annually. Traditional techniques were not adopted to cope with these change rates, and data centers are therefore having great difficulty in scaling to meet those needs.
For example, in a typical data center power distribution network, the branch distribution circuit is the area where most incidents that result in a loss of power to a receptacle typically occur. Indeed, this is where people tend to make changes in the types and amounts of load. Possibly the most common cause of electrical failure, then, is the branch circuit breaker being tripped by a person plugging in a load that exceeds the capacity of the circuit.
In a data center environment, this issue can be complicated in cases where there are thousands of branch circuits present. Also, data centers tend to maintain loading of each branch circuit at or below about 75% of its capacity to account for “inrush loads” that can occur during a cold start, when all of the connected EDP equipment is powering up simultaneously (e.g., which may include spinning up fans, disk drives, etc.). This is typically considered as the highest load scenario; and, if not accounted for, it can trip the branch circuit breakers when it happens. A further contributing factor to this issue is that many information technology (IT) or data center personnel do not always know the power demands of the equipment they are installing, especially considering that the exact configuration in which the equipment is installed can vary the power it draws considerably.
One traditional technique that is used to address this issue is power monitoring. Power monitoring devices (e.g., via plugstrips with amperage meters or Power Distribution Units (PDUs), wall mounted or free-standing units which contain distribution circuit breakers that are connected to power whips that power equipment racks on the data center floor) can be used to determine a current power draw. However, for at least the reasons discussed earlier, sudden changes in power draw can cause sudden problems, which would not be easily remedied by such devices. For example, data center staff or users can trip circuit breakers when they install new equipment, potentially causing service interruptions, which may not be detected using power monitoring devices in time to prevent the issue.
Another factor that contributes to power distribution issues is that many models of EDP equipment have only one power supply, and therefore one power cord. This tends to be even more typical of medical equipment and other types of equipment that may often be deployed into mission-critical or life safety roles. However, since they only have one power input, they can be vulnerable to downtime due to power failures. Also, having only a single power cord and/or supply can complicate maintenance, which power systems can require from time to time. In fact, this can be true even if multiple independent power sources are available, when the device can only be plugged into one power source at a time.
One traditional technique that is used to address this issue is to install auto-switching power plugstrips. However, those plugstrips are typically bulky and expensive. Further, the types that are used in data centers are usually mounted horizontally in data equipment racks. This configuration can take up valuable rack space, and tends to take even more rack space with its two input plugs connected to two different power sources.